December 19, 2002
09:00 AM (EST)

News Release Number: STScI-2002-16

A Tiny Galaxy is Born

December 19, 2002: New detailed images from NASA's Hubble Space Telescope show a "late-blooming" galaxy, a small, distorted system of gas and stars that still appears to be in the process of development, even though most of its galactic cousins are believed to have started forming billions of years ago. Evidence of the galaxy's youthfulness can be seen in the
burst of newborn stars and its disturbed shape. This evidence indicates
that the galaxy, called POX 186, formed when two smaller clumps of gas
and stars collided less than 100 million years ago (a relatively recent
event in the universe's 13-billion-year history), triggering more star
formation. Most large galaxies, such as our Milky Way, are thought to
have formed the bulk of their stars billions of years ago.

Q & A: Understanding the Discovery

1.
Why is this finding important?

The Hubble images of POX 186 support theories that all galaxies originally formed through the assembly of smaller "building blocks" of gas and stars. These galactic building blocks formed shortly after the Big Bang, the event that created the universe.

The youthful galaxy's puny size may support a recent theory of galaxy formation known as "downsizing," which proposes that the least massive galaxies in the universe are the last to form. In clear contrast to POX 186, the most massive galaxies in the universe, known as giant ellipticals, have a generally spherical structure with few or no young stars, indicating that they formed many billions of years in the past.